JP6094087B2 - Moving distance calculation method and moving distance calculation device - Google Patents

Description

  The present invention relates to a moving distance calculation method for calculating a cumulative moving distance of a moving object.

  There is known a technique for calculating the cumulative moving distance of a moving object by integrating the distances between the measurement positions of the moving object measured using a satellite positioning system typified by GPS (Global Positioning System) (for example, Patent Document 1).

JP 2003-322545 A

  If the position of the moving object measured using the satellite positioning system is accurate, the accumulated moving distance of the moving object can be correctly calculated by using the method of Patent Document 1. But this is an idealism. In the satellite positioning system, a certain error is included in the position of the moving body to be measured due to various error factors. Since the satellite signal reception environment and reception conditions change every moment, it is almost impossible to obtain an accurate position without error. For this reason, the idea of simply integrating the distances between the measurement positions has a problem in that errors are accumulated in the accumulated movement distance as they are integrated due to errors included in the measurement positions.

  When considering a device (for example, a runner's watch) that measures and displays the moving distance of a moving object, it is extremely important to correctly calculate the cumulative moving distance. Providing the user with an accurate travel distance is the original purpose of the product, so if the wrong cumulative travel distance is provided to the user, the trust of the product is impaired.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to propose a new method for correctly calculating the moving distance of the moving body.

  The first invention for solving the above-mentioned problems is to intermittently measure the position and moving direction of the moving body, and select the measurement position where the change in the moving direction satisfies the reference position selection condition as the reference position. And calculating a cumulative movement distance using a distance connecting the reference positions and a distance from the latest reference position to the latest measurement position.

  As another invention, a measurement unit that intermittently measures the position and movement direction of the moving body, a selection unit that selects a measurement position where a change in the movement direction satisfies a reference position selection condition as a reference position, and A movement distance calculation apparatus including a calculation unit that calculates a cumulative movement distance using a distance connecting the reference positions and a distance from the latest reference position to the latest measurement position may be configured.

  According to the first aspect of the invention, the position and moving direction of the moving body are measured intermittently. Then, the measurement position where the change in the measured moving direction satisfies the reference position selection condition is selected as the reference position. Then, the accumulated movement distance is calculated using the distance connecting the reference positions and the distance from the latest reference position to the latest measurement position.

  Various conditions can be set as the reference position selection condition. For example, the reference position selection condition can be set as a condition that the moving direction of the moving body changes more than a certain value. If the measurement position while the moving body is moving linearly is not located on the straight line, a longer distance than the original is accumulated. Therefore, if the moving direction of the moving body does not change more than a certain value, the reference position is not selected, and if it changes more than a certain value, the measurement position is selected as the reference position, so that an error is superimposed on the accumulated moving distance. Therefore, it is possible to calculate the cumulative movement distance close to the true cumulative movement distance.

  Further, as the second invention, the selection in the moving distance calculation method of the first invention is based on the selection of the reference position using an angle formed by the moving direction at the latest reference position and the moving direction at the measurement position. It is good also as comprising the moving distance calculation method including determining whether conditions are satisfy | filled.

  If the angle between the movement direction at the latest reference position and the movement direction at the latest measurement position is equal to or greater than a certain angle, it is considered that the movement direction of the moving body has changed. For this reason, as in the second invention, by determining whether or not the reference position selection condition is satisfied using the angle formed by the movement direction at the latest reference position and the movement direction at the measurement position, the moving body It becomes possible to select the measurement position when the movement direction of the change as the reference position.

  Further, as a third invention, the measurement in the moving distance calculation method of the first invention includes a first direction measurement that measures a moving direction of the moving body using a Doppler of a satellite signal, and the selection To determine whether or not the reference position selection condition is satisfied using an angle formed by the movement direction at the latest reference position measured in the first direction measurement and the movement direction at the measurement position. It is good also as comprising the movement distance calculation method containing.

  The moving direction of the moving body can be measured by using a satellite signal Doppler (first direction measurement). If the angle between the movement direction at the latest reference position measured in this way and the movement direction at the latest measurement position is greater than or equal to a certain value, it is considered that the movement direction of the moving body has changed significantly. Therefore, as in the third aspect, whether or not the reference position selection condition is satisfied by using the angle formed by the movement direction at the latest reference position measured in the first direction measurement and the movement direction at the latest measurement position. It is possible to select the measurement position when the moving direction of the moving body is changed as the reference position.

  Further, as a fourth invention, the measuring in the moving distance calculating method of the third invention includes a second direction measurement for measuring a moving direction from the front-rear relation of the measurement position, and the first direction measurement Measurement when the first movement direction at the measurement position measured in step 2 and the second movement direction at the measurement position measured in the second direction measurement do not satisfy a predetermined approximate condition. It is good also as comprising the movement distance calculation method further including suppressing selection to the said reference position of a position.

  The moving direction of the moving body can be measured by using a satellite signal Doppler (first direction measurement). Also, the moving direction of the moving body can be measured from the context of the measurement position (second direction measurement). If the movement directions measured by two types of measurement methods with different measurement principles are approximate, it can be determined that the reliability of the movement direction is high, that is, the reliability of the measurement position is high.

  Therefore, according to the fourth invention, the first movement direction at the measurement position measured in the first direction measurement and the second movement direction at the measurement position measured in the second direction measurement are: When the predetermined approximate condition is not satisfied, it is determined that the reliability of the measurement position is low, and selection of the measurement position as the reference position is suppressed. Thereby, it is possible not to select a measurement position with low reliability as a reference position.

  Further, as a fifth invention, the measuring in the moving distance calculation method of any one of the first to fourth inventions includes measuring the moving speed of the moving body, and the reference position selection condition is It is good also as comprising the moving distance calculation method further including changing according to the moving speed of a moving body.

  According to the fifth aspect of the invention, the reference position selection condition is changed according to the moving speed of the moving body. It can be said that there is almost no sudden change in the moving direction during high-speed movement. On the other hand, when moving at a low speed, the moving direction may change drastically. Thus, by changing the reference position selection condition according to the moving speed, it is possible to realize selection of an appropriate reference position according to the moving speed.

  Further, as a sixth invention, the measurement in the movement distance calculation method of any one of the first to fifth inventions includes measuring a moving speed of the moving body using a Doppler of a satellite signal, The moving distance calculation method further includes inhibiting selection of the measurement position as the reference position when the change condition of the measurement position and the moving speed do not satisfy the matching condition indicating that they match each other. It is good as well.

  When the change in the measurement position and the moving speed are not compatible with each other, a large error is included in the measurement position, and so-called position jump may occur. Therefore, according to the sixth aspect of the present invention, when the change condition of the measurement position and the moving speed measured using the Doppler of the satellite signal do not satisfy the matching condition indicating that they match each other, Suppress selection. Thereby, when a position jump occurs, it is possible to prevent the measurement position from being selected as the reference position.

  In the seventh invention, the calculating in the moving distance calculation method of the sixth invention is that the accumulated moving distance is calculated using the previously calculated accumulated moving distance and the moving speed when the conforming condition is not satisfied. It is good also as comprising the moving distance calculation method including updating.

  As described above, when the conformance condition is not satisfied, there is a high possibility that a position jump has occurred at the measurement position. If the cumulative movement distance is calculated using the position where the position jump has occurred, a value greatly deviating from the true cumulative movement distance may be calculated. Therefore, according to the seventh aspect, when the conforming condition is not satisfied, the accumulated movement distance is updated using the previously calculated accumulated movement distance and movement speed. Thereby, it is possible to prevent an erroneous accumulated movement distance from being calculated.

Explanatory drawing of the principle of reference position selection and movement distance calculation. Explanatory drawing of the principle of reference position selection and movement distance calculation. The figure which shows an example of a position jump condition. The figure which shows an example of a moving direction change condition. The figure which shows an example of elapsed time conditions. Runners watch external view. The block diagram which shows the function structural example of a runner's watch. The figure which shows the data structural example of GPS output data. The figure which shows the data structural example of reference | standard position setting data. The flowchart which shows the flow of a main process. The flowchart which shows the flow of a reference | standard position acceptance / rejection determination process. (1) A diagram showing an example of experimental results in an open sky environment. (2) A figure showing an example of an experimental result in a multipath environment. The figure which shows the data structural example of orientation difference threshold value setting data. The figure which shows the data structural example of threshold time setting data.

  Hereinafter, an example of a preferred embodiment to which the present invention is applied will be described. This embodiment is an embodiment for calculating a moving distance of a moving body. In this embodiment, the position of a moving body is measured using GPS, which is a kind of satellite positioning system. Then, the moving distance of the moving body is calculated based on the measurement position.

1. Principle A reference point selection method and a movement distance calculation method in this embodiment will be described. In the present embodiment, the cumulative moving distance of a moving body including a GPS receiver that calculates a position and a moving speed is calculated using a GPS satellite signal received from a GPS satellite that is a kind of positioning satellite signal. The moving body is various moving bodies such as humans, automobiles, and bicycles.

  The GPS receiver is configured to be able to intermittently measure a position, a moving speed, and a moving direction using a GPS satellite signal received from a GPS satellite. A movement speed and a movement direction will be comprehensively described as a movement speed vector. As a general rule, the speed of movement (scalar amount) is simply expressed as moving speed. That is, the moving speed means “Speed”, and the moving speed vector means “Velocity”.

  In this embodiment, the GPS receiver installed in the moving body measures the position and moving speed vector intermittently at 1 second intervals. The position of the moving body can be measured by performing a known position calculation using information such as the positions of a plurality of GPS satellites and pseudo distances to the GPS satellites. The pseudorange can be calculated using the phase (code phase) of the spreading code of the GPS satellite signal received from the GPS satellite.

  Also, the moving speed vector can be measured using a GPS satellite signal Doppler. More specifically, Doppler is caused by a change in the relative position between the GPS satellite and the GPS receiver, that is, a relative velocity. The Doppler is obtained by projecting the relative velocity vector between the GPS receiver and the GPS satellite in the line-of-sight direction from the GPS receiver toward the GPS satellite. Therefore, the moving speed vector of the GPS receiver can be calculated using Doppler.

  In the present embodiment, the distance between the measurement positions is not accumulated as in the prior art to calculate a cumulative travel distance (hereinafter referred to as “cumulative travel distance” in the present embodiment). Select the measurement position where the change in the movement direction satisfies the specified reference position selection condition as the reference position, and use the distance connecting the reference position and the distance from the latest reference position to the latest measurement position to perform cumulative movement Calculate the distance.

  FIG. 1 is an explanatory diagram of a method for selecting a reference position. The big idea of the selection of the reference position in this embodiment is that the measurement position is not selected as the reference position at the timing when the moving direction of the moving body has not changed so much, and the timing at which the moving direction of the moving body is considered to have changed to some extent. The measurement position is selected as the reference position. Specifically, as a reference position selection condition, it is determined whether or not a predetermined movement direction change condition is satisfied, and when it is determined that the movement direction change condition is satisfied, the measurement position at that time is determined as the reference position. Select as

  FIG. 1 illustrates an example of a temporal change in the position and moving direction of a moving body measured in time series. Specifically, for example, the position of the moving body and the moving direction of the moving body, which are sequentially measured at a time interval such as 1 second, are shown, and FIG. 1 shows a view focusing on times t10 to t19. In FIG. 1, the measurement position is indicated by a white circle, the measurement position selected as the reference position is indicated by a black circle in the white circle, and the moving direction of the moving body is indicated by an arrow. Further, the distance between the reference positions expressed as the distance between adjacent reference positions is indicated by a thick solid line.

  In the vicinity of the measurement position, the measurement time at the measurement position is described. Moreover, the azimuth which shows the said moving direction is shown in the vicinity of the arrow which shows the moving direction of a moving body. However, the azimuth angle shown here is described for explanation, and the arrow indicating the moving direction does not always point in the direction indicated by the azimuth angle.

  Here, as an example of the moving direction change condition, the difference between the azimuth at the latest measurement time and the azimuth at the time when the reference position was most recently selected in the past (hereinafter referred to as “azimuth difference”). A method of detecting a change in the moving direction of the moving body based on the above is illustrated. At each measurement time in the figure, a numerical value surrounded by a rectangle described adjacent to the azimuth represents the magnitude of the azimuth difference at the measurement time.

  If the azimuth at the latest measurement time and the azimuth at the time when the reference position was most recently selected in the past are significantly different, it can be considered that the moving direction of the moving body has changed. Therefore, threshold determination is performed on the absolute value of the azimuth difference. If the threshold is exceeded, it is determined that the moving direction of the moving object has changed. Then, the measurement position at the measurement time is selected as the reference position.

  A specific description will be given with reference to FIG. Here, the description will be made assuming that the threshold value of the azimuth difference (hereinafter referred to as “azimuth difference threshold value”) is “15 degrees”. The measurement position at time t10 is selected as the reference position. The azimuth angle at time t10 is 80 degrees. For this reason, the moving direction (azimuth angle) at time t10 is set as a reference moving direction (reference azimuth angle).

  At time t11, 81 degrees is obtained as the azimuth angle. The difference in orientation between time t10 and time t11 is “81 degrees−80 degrees = 1 degree”. This is smaller than the heading difference threshold (15 degrees). Therefore, the measurement position at time t11 is not selected as the reference position. Similarly, at time t12, the orientation difference is “85 degrees−80 degrees = 5 degrees”, and at time t13, the orientation difference is “92 degrees−80 degrees = 12 degrees”. Since these are all smaller than the azimuth difference threshold of 15 degrees, these measurement positions are not selected as reference positions.

  At time t14, 98 degrees is obtained as the azimuth angle. The difference in orientation between time t10 and time t14 is “98 degrees−80 degrees = 18 degrees”. This exceeds the bearing difference threshold (15 degrees). Therefore, it is determined that the moving direction of the moving body has changed, and the measurement position at time t14 is selected as the reference position. Since the reference position is newly selected, the reference movement direction is switched to the movement direction at time t14.

  At time t15, 118 degrees is obtained as the azimuth angle. The difference in orientation between time t14 and time t15 is “118 degrees−98 degrees = 20 degrees”. This exceeds the bearing difference threshold (15 degrees). Therefore, it is determined that the moving direction of the moving body has changed, and the measurement position at time t15 is selected as the reference position. Since the reference position is newly selected, the reference movement direction is switched to the movement direction at time t15.

  At time t16 and time t17, the azimuth differences from time t15 are 2 degrees and 4 degrees, respectively, and these are both smaller than the azimuth difference threshold (15 degrees), so the measurement positions at these times are used as reference positions. Do not select.

At time t19, 137 degrees is obtained as the azimuth angle. Therefore, the orientation difference between time t15 and time t19 is “137 degrees−118 degrees = 19 degrees”. This exceeds the bearing difference threshold (15 degrees). Therefore, it is determined that the moving direction of the moving body has changed, and the measurement position at time t19 is selected as the reference position.
The same applies hereinafter.

  Next, a method for calculating the movement distance will be described. In the present embodiment, the movement distance is calculated at the same time interval as the position measurement time interval. For example, if position measurement is performed at 1 second intervals, the movement distance is calculated / updated at 1 second intervals accordingly.

  Specifically, for a reference position selected in chronological order, a distance between two adjacent reference positions (hereinafter referred to as “distance between reference positions”) is calculated. Then, the distance from the latest reference position to the latest measurement position is added to the distance obtained by integrating the distances between the reference positions from the measurement start point (hereinafter referred to as “interval between reference positions”). The value is calculated as the cumulative movement distance.

  A description will be given with reference to FIG. 1 again. In FIG. 1, the movement distance at time t10 is an integrated distance between reference positions obtained by integrating all distances between reference positions obtained before time t10. Here, the integrated distance between the reference positions obtained before time t10 is D0.

  At time t11, a value obtained by adding a distance d11 from the reference position at time t10 to the measurement position at time t11 to the integrated distance between reference positions D0 at time t10 is set as the cumulative movement distance at time t11. That is, the cumulative movement distance at time t11 is “D0 + d11”.

At time t12, a value obtained by adding the distance d12 from the reference position at time t10 to the measurement position at time t12 to the integrated distance D0 between reference positions at time t10 is set as the cumulative movement distance at time t12. That is, the cumulative moving distance at time t12 is “D0 + d12”.
Similarly, the cumulative movement distance at time t13 is “D0 + d13”.

  Next, when the cumulative movement distance is calculated in the same manner at time t14, “D0 + d14” is obtained. Here, at time t14, the measurement position is selected as the reference position. Therefore, the distance d14 from the reference position at time t10 to the measurement position at time t12 is set as the reference position distance D1, and this value is stored (D1 = d14).

  At time t15, the cumulative movement distance is obtained by adding the distance d15 from the reference position at time t14 to the measurement position at time t15 to the integrated distance between reference positions at time t14. The accumulated distance between the reference positions at time t14 is “D0 + D1”. Therefore, the cumulative moving distance at time t15 is “D0 + D1 + d15”. Here, at time t15, the measurement position is selected as the reference position. Therefore, the distance d15 is set as the reference position distance D2, and this value is stored (D2 = d15).

  The same applies to the following. For example, since the measurement position is selected as the reference position at time t18, the cumulative movement distance is “D0 + D1 + D2 + D3”. As described above, in the present embodiment, the cumulative movement distance is calculated by adding the distance from the latest reference position to the latest measurement position to the accumulated distance between reference positions obtained by integrating the distances between the reference positions. .

  In this embodiment, the selection of the reference position and the calculation of the cumulative movement distance are performed in this way. However, in GPS, the so-called position jump, in which the measurement position is greatly displaced according to the reception environment and reception status of the GPS satellite signal, is performed. May occur. If a measurement position is selected as a reference position when a position jump occurs, a large error occurs in the accumulated movement distance calculated as described above. There may be a case where a position far away in a direction different from the moving direction of the moving body is obtained as the measurement position, and the cumulative moving distance is calculated longer than the original moving distance.

  In order to avoid this problem, in the present embodiment, it is determined whether or not a predetermined position jump condition indicating that a position jump has occurred, and when this position jump condition is met, Suppress selection to the reference position.

  FIG. 3 is a diagram illustrating an example of the position skip condition. Specifically, “the absolute value of the difference between the current speed reference calculation distance and the current position reference calculation distance exceeds a predetermined threshold distance” is defined as the position skip condition. The speed reference calculation distance is a movement distance per unit time obtained from a movement speed and a unit time interval. The position reference calculation distance is a movement distance per unit time obtained from a measurement position that fluctuates in time. Here, the unit time refers to a time interval of position measurement (1 second in the present embodiment).

  According to the position jump condition of FIG. 3, a position jump occurs when the absolute value of the difference between the movement distance calculated based on the movement speed and the movement distance calculated based on the position exceeds a predetermined threshold distance. Is determined. This corresponds to a case where the matching condition indicating that the change in the measurement position and the moving speed are compatible with each other is not satisfied. In this case, selection of the measurement position as the reference position is suppressed.

  FIG. 2 is an explanatory diagram of a method for selecting a reference position and calculating a movement distance when a position jump occurs. The way of viewing the figure is the same as in FIG. The simple figure for demonstrating position jump was shown in the lower part of FIG. Consider two measurement positions, a measurement position P (t) at a certain time t and a measurement position P (t + 1) at the next time t + 1. Let V (t) be the moving speed vector of the moving body at time t.

  In this case, the predicted position of the moving body predicted from the moving speed vector V (t) and the measurement position P (t) is P ′ (t + 1). From the moving speed vector, the moving speed and moving direction of the moving body are obtained. If the moving speed of the moving object is known, the moving distance per unit time and the moving direction are also determined, so that the position of the moving object at the next time can be predicted. The measurement position P (t) is indicated by a white circle, the prediction position P ′ (t + 1) is indicated by a dotted white circle, and the distance between the measurement position P (t) and the prediction position P ′ (t + 1) is a speed reference calculation distance. Is “dj”.

  On the other hand, a measurement position P (t + 1) is obtained at time t + 1 by position measurement using GPS. The measurement position P (t + 1) is indicated by a hatched circle. However, a position jump occurs at the measurement position P (t + 1) due to some error factor. The distance between the measurement position P (t) and the measurement position P (t + 1) is the position reference calculation distance, and this is “di”.

  According to the position skip condition in FIG. 3, it is determined that a position jump has occurred when the condition | dj−di |> dθ is satisfied. However, “dθ” is a predetermined threshold distance (for example, 10 meters).

  In FIG. 2, position jumps occur at time t13 and time t14. At time t13, the azimuth difference is 12 degrees, which is smaller than the azimuth difference threshold of 15 degrees. Therefore, the measurement position is not selected as the reference position regardless of whether or not a position jump occurs. However, since the azimuth difference is 18 degrees at time t14 and exceeds the azimuth difference threshold of 15 degrees, the reference position selection criterion described in FIG. 1 is satisfied. However, since a position jump occurs at time t14, the measurement position at time t14 is not selected as the reference position.

  This is a method of calculating the movement distance when a position jump occurs, but when a position jump occurs, the cumulative movement distance is not calculated using the distance between the reference position and the measurement position. The cumulative moving distance is calculated using the moving speed and the unit time interval. Specifically, the moving distance per unit time is calculated by multiplying the moving speed by the unit time, and this is added to the latest accumulated moving distance to newly calculate the accumulated moving distance of the moving body.

  Specifically, a position jump occurs at time t13. Therefore, for example, the cumulative travel distance d13 at time t13 is calculated using the cumulative travel distance d12 at time t12 immediately before the position jump occurs, the travel speed v12 at time t12, and the unit time interval Δt. To do. Specifically, “d13 = d12 + v12 · Δt” is set.

  Similarly, a position jump occurs at time t14. Therefore, for example, the cumulative travel distance d14 at time t14 is calculated using the cumulative travel distance d13 at time t13, the travel speed v13 at time t13, and the unit time interval Δt. Specifically, “d14 = d13 + v13 · Δt”.

  In this case, the measurement position at time t14 is not selected as the reference position. As a result, the measurement position selected as the reference position next to time t10 is the measurement position at time t15. Therefore, the distance d15 between the measurement position at time t10 and the measurement position at time t15 is the reference inter-position distance D1.

  In FIG. 1 and FIG. 2, as an example of the reference position selection condition, the position change condition using the angle formed by the movement direction at the latest reference position and the movement direction at the latest measurement position is illustrated. Other position change conditions can be considered.

  FIG. 4 shows a specific example of the moving direction change condition, and shows a list of moving direction change conditions in a table format. In this table, the condition number indicating the number of the position change condition is shown. And the condition contents indicating the condition contents are defined in association with each other.

  The first moving direction change condition defines that “the absolute value of the difference between the current speed direction and the speed direction at the previous selection reference position exceeds the first direction difference threshold value”. The speed direction is a moving direction obtained from a moving speed vector. In other words, based on the moving direction (speed azimuth) of the moving body measured by the calculation of the GPS moving speed vector, when the current speed azimuth and the speed azimuth at the previously selected reference position are more than a certain distance, It is determined that the moving direction of the moving body has changed. This is the moving direction change condition illustrated in FIGS. 1 and 2.

  The second moving direction change condition defines that “the absolute value of the difference between the current speed direction and the previous speed direction exceeds the second direction difference threshold”. The point that the change of the moving direction is determined based on the moving direction (speed direction) of the moving body measured by the GPS moving speed vector calculation is the same as the first condition. However, in the second condition, it is determined that the moving direction of the moving body has changed when the current speed direction and the previous speed direction are more than a certain distance.

  The third moving direction change condition is “(A) the absolute value of the difference between the current position direction and the previous position direction exceeds the third direction difference threshold, and (B) the current position direction. And the current speed azimuth is less than a fourth azimuth difference threshold, and (C) the estimated position error is less than a predetermined error threshold ".

  The position direction is the moving direction of the moving body obtained from the measurement positions that move back and forth in time. Unlike the first and second conditions, a change in the moving direction of the moving object is determined based on the moving direction of the moving object determined from the measurement positions that change in time. However, the condition setting for the third condition is more complicated than the first and second conditions. This is because in GPS, an error is likely to occur in position measurement.

  The condition (A) is a condition for estimating that the moving direction of the moving body has changed when the current position direction and the previous position direction are more than a certain distance. In GPS, the position is calculated using a pseudo distance, but the pseudo distance is likely to contain an error. A typical example is a multipath environment. If there is an obstacle such as a building around the moving body, the GPS satellite signal sent from the GPS satellite does not reach the GPS receiver directly, but is reflected or diffracted by the obstacle etc. and reaches the GPS receiver. To do.

  In this case, an error occurs in the code phase observed in the GPS receiver, and an error occurs in the pseudorange calculated using this code phase. Due to the error in the pseudo distance, the error is superimposed on the position to be measured. In the third condition, since the movement direction is obtained from the measurement position, the measurement error is an error in the movement direction. Therefore, in the third condition, in addition to the condition (A), a condition (B) and a condition (C) for determining the reliability of the measurement position are added.

  The condition (B) is a condition indicating that the difference between the current position direction and the current speed direction is approximate. Since Doppler is not easily affected by multipath, the accuracy of measurement of moving speed and moving direction is not so lowered even in a multipath environment. Therefore, the position azimuth measured at the same time and the velocity azimuth are compared, and if both are approximated, it is determined that the reliability of the measurement position is high.

  Condition (C) is a condition indicating that the estimated position error is small. In GPS, when performing position measurement, the magnitude of an error included in the measurement position can be estimated. The estimated position error is a parameter commonly known as position sigma. Since the method for calculating the position sigma is conventionally known, description using mathematical formulas and the like is omitted here. If the estimated position error is small, it can be determined that the reliability of the measurement position is high.

  The fourth moving direction change condition is “(A) the absolute value of the difference between the current position direction and the previous position direction exceeds the third direction difference threshold, and (B) the current position direction. And the current speed direction are less than the fourth direction difference threshold value, and (D) the good measurement environment condition is satisfied ”.

  Condition (A) and condition (B) are the same as the third position direction change condition. Condition (D) is a condition indicating that the position measurement environment is favorable. Whether or not the position measurement environment is good is based on, for example, the intensity of the GPS satellite signal received from the GPS satellite (received signal intensity), the sky arrangement of the GPS satellite (DOP value), the elevation angle of the GPS satellite, and the like. A comprehensive judgment can be made.

  For example, among the captured GPS satellites, there are a predetermined number or more (for example, 5 or more) of satellites whose received signal intensity is equal to or greater than a predetermined threshold and whose elevation angle is equal to or greater than a predetermined elevation threshold (for example, 45 degrees) Then, it is determined that the good measurement environment condition of the condition (D) is satisfied. Note that this condition is merely an example, and it goes without saying that the setting can be changed as appropriate based on the above elements.

  The first to fourth conditions shown in FIG. 4 can be used, for example, as an OR condition for determining the change in the moving direction. That is, when any one of the first to fourth conditions is satisfied, it is determined that the moving direction change condition is satisfied, and the measurement position is selected as the reference position.

  By the way, when the user travels linearly without changing the moving direction or when the user travels while changing the moving direction gently, the moving direction changing condition shown in FIG. In some cases, the reference position may not be selected after a long time. In this embodiment, since the cumulative movement distance is calculated based on the reference position, if the reference position is not set for a long time, there is a possibility that an error occurs in the cumulative movement distance.

  Therefore, in the present embodiment, a predetermined elapsed time condition is defined, and when this elapsed time condition is satisfied, the measurement position is selected as the reference position regardless of whether or not the moving direction change condition is satisfied. .

  FIG. 5 is a diagram illustrating an example of the elapsed time condition. The elapsed time condition defines that “the elapsed time since the previous reference position was selected exceeds a predetermined threshold time”. That is, the reference position is forcibly set when a predetermined time or more has passed since the previous reference position was selected.

2. Embodiment Next, an embodiment of a movement distance calculation apparatus that calculates a movement distance based on the above principle will be described. Here, a runner's watch will be described as an example of an electronic device equipped with a moving distance calculation device. However, it goes without saying that the embodiments to which the present invention can be applied are not limited to the embodiments described below.

2-1. External Configuration FIG. 6 is a schematic external view of the runners watch 1 in the present embodiment. The runner's watch 1 is a wrist-worn type small electronic device that is used with a moving body being a human being and worn on a user's wrist (right wrist or left wrist). The main components are a main body 2 and a band. Part 3.

  The band unit 3 is a mounting tool for fixing and mounting the main body unit 2 on the user's wrist, and has a known configuration. For example, a band provided with a hook-and-loop fastener or a shrinkable rubber band can be considered as a configuration for realizing the ease of mounting the main body 2 at a low cost.

  The main body 2 is the main body of the runner's watch 1 and is configured to have operation buttons 4 on the side, a liquid crystal display 5 in the center of the front, and a speaker 6 on the upper front. The operation buttons 4 are used for the user to input personal data and to instruct the start and end of measurement of travel distance. The liquid crystal display 5 displays information such as lap time and travel distance. From the speaker 6, voice guidance, pace sound, and the like are output.

  The main body 2 incorporates a GPS antenna (not shown) that receives a GPS satellite signal from a GPS satellite that is a type of positioning satellite. The main body 2 has a control board on which a rechargeable battery 8 that is charged via a charging terminal provided at a predetermined position (for example, a side surface of the main body), a microprocessor, a memory, a communication module, a GPS module, and the like are mounted. 9 is built-in.

2-2. Functional Configuration FIG. 7 is a block diagram illustrating an example of a functional configuration of the runners watch 1. The runner's watch 1 includes a GPS antenna 7, a processing unit 10, a GPS module 20, a sensor unit 30, an operation unit 40, a display unit 50, a sound output unit 60, a communication unit 70, and a clock unit 80. And a storage unit 90.

  The processing unit 10 is a processor that comprehensively controls each unit of the runner's watch 1 according to various programs such as a system program stored in the storage unit 90, such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor). Constructed with a processor.

  In the present embodiment, the processing unit 10 includes a reference position acceptance / rejection determination unit 11, a movement distance calculation unit 13, and a display control unit 15 as main functional units. However, these functional units are only described as one embodiment, and all the functional units are not necessarily required as essential components. Moreover, it is good also considering a function part other than these as an essential component.

The reference position acceptance / rejection determination unit 11 performs acceptance / rejection determination as to whether or not to adopt (select) a position newly measured by the GPS module 20 as a reference position according to the above principle.
The travel distance calculation unit 13 calculates the cumulative travel distance of the own device as the travel distance of the user according to the above principle.
The display control unit 15 performs control for causing the display unit 50 to display information such as the travel distance calculated by the movement distance calculation unit 13.

  The GPS module 20 is a module that calculates a position and a moving speed vector using a GPS satellite signal received by the GPS antenna 7. The GPS module 20 performs signal processing on an RF (Radio Frequency) signal received by the GPS antenna 7 to capture a GPS satellite signal, and various quantities related to the captured GPS satellite signal (hereinafter referred to as “measurement information”). ) Is calculated and acquired.

  The measurement information includes various quantities such as the code phase and Doppler (also referred to as Doppler frequency) of the signal received from the GPS satellite signal, and various quantities such as the pseudorange and the pseudorange change rate between the runners watch 1 and the GPS satellite. It is. Using this measurement information, the GPS module 20 performs a known position calculation and a movement speed vector calculation to calculate the position and movement speed vector of the own device. The GPS module 20 corresponds to a measurement unit that intermittently measures the position of a moving body based on satellite signals.

  The sensor unit 30 is a sensor unit that includes an inertial sensor such as an acceleration sensor or a gyro sensor. The detection result of the sensor unit 30 is output to the processing unit 10.

  The operation unit 40 is an input device configured to include, for example, a touch panel, a button switch, and the like, and outputs a pressed key or button signal to the processing unit 10. The operation unit 40 corresponds to the operation button 4 in FIG.

  The display unit 50 is a display device that includes an LCD (Liquid Crystal Display) or the like, and performs various displays based on display signals output from the processing unit 10. The display unit 50 corresponds to the liquid crystal display 5 of FIG.

  The sound output unit 60 is a sound output device configured with a speaker or the like, and performs various sound outputs based on the sound output signal output from the processing unit 10. The sound output unit 60 corresponds to the speaker 6 of FIG.

  The communication unit 70 is a communication device for transmitting / receiving information used inside the device to / from an external information processing device under the control of the processing unit 10. As a communication method of the communication unit 70, a wired connection via a cable conforming to a predetermined communication standard, a connection connected via an intermediate device that is also used as a charger called a cradle, or short-range wireless communication is used. Various systems such as a wireless connection type can be applied.

  The timepiece unit 80 is an internal timepiece of the runner's watch 1 and includes a crystal oscillator including a crystal resonator and an oscillation circuit. The time measured by the clock unit 80 is output to the processing unit 10 as needed.

  The storage unit 90 includes a storage device such as a ROM (Read Only Memory), a flash ROM, and a RAM (Random Access Memory), and the processing unit 10 controls the runner's watch 1 and various applications. Various programs and data for executing processing are stored.

  The storage unit 90 stores a main program 91 that is read by the processing unit 10 and executed as a main process (see FIG. 10). The main program 91 includes a reference position acceptance / rejection determination program 911 executed as a reference position acceptance / rejection determination process (see FIG. 11) as a subroutine. These processes will be described later in detail using a flowchart.

  The storage unit 90 also stores GPS output data 93, reference position setting data 95, and cumulative travel distance data 97 as data.

  The GPS output data 93 is output data from the GPS module 20, and an example of the data configuration is shown in FIG. In the GPS output data 93, a time 931, a measurement position 933, a position estimation error 935, and a measurement movement speed vector 937 are associated with each other and stored in time series.

  The reference position setting data 95 is data relating to the set reference position, and an example of the data configuration is shown in FIG. In the reference position setting data 95, a time 951, a reference position 953, and a distance 955 between the reference positions are associated with each other and stored in time series.

  The accumulated movement distance data 97 is data in which the accumulated movement distance calculated by the movement distance calculation unit 13 is stored.

2-3. Processing Flow FIG. 10 is a flowchart showing the flow of main processing executed by the processing unit 10 in accordance with the main program 91 stored in the storage unit 90. In this main process, it is assumed that the GPS module 20 captures a GPS satellite signal, measures the position and the moving velocity vector at any time, and can obtain a measurement result from the GPS module 20 at any time.

  The processing unit 10 waits until the calculation of the movement distance is started (Step A1; No), and when it is determined that the calculation of the movement distance is started (Step A1; Yes), the data is acquired from the GPS module 20 (Step S1). A3). And based on the acquired data, the starting point of movement distance calculation is registered (step A5). Then, calculation of the movement distance is started.

  Next, the processing unit 10 acquires data from the GPS module 20 and stores it in the GPS output data 93 of the storage unit (step A9). And the process part 10 performs a reference | standard position acceptance / rejection determination process according to the reference | standard position acceptance / rejection determination program 911 memorize | stored in the memory | storage part 90 (step A11).

FIG. 11 is a flowchart showing the flow of the reference position acceptance / rejection determination process.
The reference position acceptance / rejection determination unit 11 determines whether or not the position skip condition shown in FIG. 3 is satisfied (step B1). If it is determined that the position jump condition is satisfied (step B1; Yes), it is acquired from the GPS module 20. It is determined that the latest measurement position is not adopted as the reference position (not adopted) (step B3).

  When it is determined in step B1 that the position jump condition is not satisfied (step B1; No), the reference position adoption determination unit 11 determines whether or not the movement direction change condition shown in FIG. B5). And when it determines with having been established (step B5; Yes), it determines with employ | adopting the newest measurement position as a reference position (step B7).

  When it is determined in step B5 that the moving direction change condition is not satisfied (step B5; No), the reference position acceptance / rejection determination unit 11 determines whether or not the elapsed time condition shown in FIG. B9). And when it determines with having been established (step B9; Yes), it determines with employ | adopting the newest measurement position as a reference position (step B11).

  When it is determined in step B9 that the moving direction change condition is not satisfied (step B9; No), the reference position adoption determination unit 11 determines that the latest measurement position is not adopted as the reference position (not adopted). (Step B13).

  After step B3, B7, B11 or B13, the reference position acceptance / rejection determination unit 11 ends the reference position acceptance / rejection determination processing.

  Returning to the main process of FIG. 10, after the reference position acceptance / rejection determination process, based on the acceptance / rejection determination result, the processing unit 10 determines that the determination result is “adopted” (step A13; adopted) and the latest reference position. The distance from the previous reference position is calculated as the distance between the reference positions, and stored in the reference position setting data 95 of the storage unit 90 (step A15). Then, the movement distance calculation unit 13 calculates and updates the accumulated movement distance D by adding the distances between the reference positions stored in the reference position setting data 95 (step A17).

  If the acceptance / rejection determination result is “non-adopted” (step A13; non-adopted), the processing unit 10 determines whether or not a position jump has occurred (step A19). If it is determined that no occurrence has occurred (step A19; none), the movement distance calculation unit 13 calculates a distance da between the latest reference position and the current measurement position (step A21). Then, the movement distance calculation unit 13 adds the calculated distance da to the movement distance Ds from the start point to the latest reference position to update the accumulated movement distance D (step A23).

  If it is determined in step A19 that a position jump has occurred (step A19; present), the movement distance calculation unit 13 calculates a movement distance db per unit time using, for example, the previous movement speed (step A25). Then, the travel distance calculation unit 13 adds the calculated distance db to the latest cumulative travel distance D and updates the cumulative travel distance D (step A27). When calculating the moving distance db, the current moving speed may be used instead of the previous moving speed. Alternatively, an average moving speed obtained by averaging the previous moving speed and the current moving speed may be used.

  After step A17, A23 or A27, the display control unit 15 updates the display of the accumulated movement distance on the display unit 50 with the newly calculated accumulated movement distance (step A29).

  Next, the processing unit 10 determines whether or not to end the processing (step A31). For example, it is determined whether or not the user has instructed the end of the travel distance measurement via the operation unit 40. When it determines with continuing a process (step A31; No), the process part 10 returns to step A9. If it is determined that the process is to be terminated (step A31; Yes), the main process is terminated.

2-4. Experimental Results Next, experimental results in the case where an experiment for actually calculating the cumulative moving distance is performed using the runners watch 1 of the above embodiment will be described.

  FIG. 12A is a diagram illustrating a result of an experiment for calculating the cumulative travel distance in a certain open sky environment. In an open sky environment, an experiment was conducted in which a user wearing the Runners Watch 1 traveled a course of 4971 m and the cumulative travel distance was calculated. In this figure, the locus connecting the measurement positions measured by the GPS module 20 is indicated by a dotted line, and the locus connecting the reference positions selected by the method of the present embodiment is indicated by a solid line.

  Since the experimental environment is an open sky environment, there is no significant error in the measurement position, but it can be seen that the trajectory connecting the measurement position is gritty in some places. On the other hand, the trajectory connecting the reference positions draws a smooth trajectory. When the accumulated movement distance was calculated by integrating the distances between the measurement positions, it was 6190 m. This is an error of about + 25% compared to the true distance. On the other hand, when the accumulated movement distance was calculated using the distance between the reference positions, it was 5012 m. This is an error of less than 1% with respect to the true distance, and it can be seen that the accumulated movement distance can be calculated with high accuracy.

  FIG. 12 (2) is a diagram illustrating a result of an experiment for calculating a cumulative movement distance in a multipath environment in an urban area. In a multipath environment, an experiment was performed in which a user wearing the runners watch 1 traveled a course of 2853 m and the cumulative travel distance was calculated. The way of viewing the figure is the same as in FIG.

  Since it is a multipath environment, position measurement is not performed correctly, and a large fluctuation occurs in the measurement position. However, the trajectory connecting the reference positions is substantially a trajectory along the original traveling course. When the accumulated movement distance was calculated by integrating the distances between the measurement positions, it was 4777 m. This is an error of about + 67% compared to the true distance. On the other hand, when the cumulative movement distance was calculated using the distance between the reference positions, it was 2781 m. This is an error of about 3% with respect to the true distance, and it can be seen that the cumulative moving distance can be calculated with high accuracy even in a multipath environment.

2-5. Effects In the runner's watch 1, the GPS module 20 intermittently measures the position of the moving body and the moving speed vector (moving speed and moving direction) using the GPS satellite signal. Then, the reference position acceptance / rejection determination unit 11 selects and adopts a measurement position where the change in the movement direction measured by the GPS module 20 satisfies the reference position selection condition as the reference position. Various conditions can be applied as the reference position selection condition. For example, it can be determined that the moving direction of the moving body changes more than a certain value.

  If the measurement position while the moving body is moving linearly is not located on the straight line, a longer distance than the original is accumulated. Therefore, the measurement position is not selected as the reference position if the moving direction of the moving body does not change more than a certain value, and the measurement position is selected as the reference position when it changes more than a certain value. And by using the distance connecting the reference position and the distance from the latest reference position to the latest measurement position, it is possible to prevent the accumulated movement distance from accumulating errors by calculating the accumulated movement distance, It is possible to calculate a movement distance close to the true movement distance.

  The reference position acceptance / rejection determination unit 11 determines whether or not the reference position selection condition is satisfied using an angle formed by the movement direction at the latest reference position and the movement direction at the measurement position. Specifically, when the difference between the current speed direction and the speed direction at the previous selection reference position exceeds the first direction difference threshold, it is determined that the moving direction of the moving object has changed, and a new Select the measured position as the reference position. This makes it possible to select the measurement position when the moving direction of the moving body changes as the reference position.

  In addition, the reference position adoption determination unit 11 determines whether or not the reference position selection condition is satisfied using an angle formed by the latest movement direction and the previous movement direction. Specifically, when the difference between the current speed direction and the previous speed direction exceeds the second direction difference threshold, it is determined that the moving direction of the moving body has changed, and the newly measured measurement position Is selected as the reference position. Also in this case, the measurement position when the moving direction of the moving body changes can be selected as the reference position.

  The reference position acceptance / rejection determination unit 11 determines the change in the moving direction of the moving body based on whether or not the difference in the direction of the position change obtained from the front-rear relationship of the measurement position exceeds the third orientation difference threshold value. However, in GPS, the accuracy of position measurement may be reduced depending on the reception environment and reception status of GPS satellite signals. If the measurement position cannot be obtained correctly, naturally the position obtained from the context of the measurement position The direction of change is also incorrect.

  Therefore, the moving direction (speed direction) measured using the Doppler of the GPS satellite signal is compared with the moving direction (position direction) obtained from the front-rear relationship of the measurement position, and the direction difference is less than the fourth direction difference threshold. It is determined whether or not. Based on the determination result, the reliability of the measurement position is determined. And even if it is a case where the difference of the direction of a position change is over the 3rd direction difference threshold, when it is judged that the reliability of a measurement position is low, a newly measured position is made into a reference position. Suppress selection. Thereby, it is possible not to select a measurement position with low reliability as a reference position.

  In addition, in the GPS, a so-called position jump may occur due to an error mixed in measurement information (mainly code phase) used for position measurement. If a position jump occurs and the measurement position is selected as the reference position, in many cases, the accumulated movement distance is measured longer than the original. Therefore, it is determined whether or not a matching condition indicating that the change in the measurement position and the moving speed are compatible with each other. If this matching condition is not satisfied, it is determined that a position jump has occurred and the measurement position is The selection to the reference position is suppressed. Thereby, it is possible not to select the position where the position jump has occurred as the reference position.

  Further, in the present embodiment, when the above-described conforming condition is not satisfied, the accumulated movement distance is updated using the previously calculated accumulated movement distance and movement speed. Specifically, if the conformance condition is not satisfied, it is determined that a position jump has occurred, and instead of calculating the cumulative movement distance using the distance from the previously selected reference position to the latest measurement position, for example, The cumulative movement distance is calculated using the movement distance obtained from the movement distance measured at the previous time and the time interval of position measurement. Thereby, when a position jump occurs, it is possible to prevent the cumulative movement distance that is greatly different from the original value from being calculated.

3. Modifications Embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, modified examples will be described.

3-1. Mobile body The mobile body is not limited to a human being, but may be various mobile bodies such as bicycles, automobiles, and trains. By using the movement distance calculation device of the present invention, it is possible to calculate the accumulated movement distances of various moving objects.

3-2. Electronic Device The movement distance calculation device of the present invention can be used by being built in various electronic devices. Not only the runner's watch of the above-mentioned embodiment, but can be provided in various electronic devices such as a portable phone (including a smartphone), a portable navigation device, a personal computer, a PDA (Personal Digital Assistance), and a pedometer. is there.

  Further, when considering a wearable small electronic device that is worn on a predetermined part of a human being, it is not always necessary to be a wrist-worn small electronic device. For example, an upper arm wearable small electronic device to be worn on the upper arm is used. It is good.

3-3. Satellite positioning system The satellite positioning system is not limited to GPS, but may be a satellite positioning system such as WAAS (Wide Area Augmentation System), QZSS (Quasi Zenith Satellite System), GLONASS (GLObal NAvigation Satellite System), and GALILEO.

3-4. Types of reference position selection conditions The reference position selection conditions described in the above embodiment are merely examples, and other conditions can naturally be determined. For example, when it is determined that the position measurement has been performed continuously and accurately for a predetermined time, the latest measurement position when the predetermined time has elapsed may be selected as the reference position.

  As a condition in this case, for example, the condition (B) in the third condition of the moving direction change condition in FIG. 4 is used, and “the number of times that the condition (B) is continuously satisfied is equal to or more than a predetermined threshold number of times. Can be determined as a reference position selection condition. As described above, if the current position azimuth and the current speed azimuth are approximate, there is a high possibility that the position measurement has been accurately performed. Therefore, when the condition (B) is continuously satisfied, it is determined that the accuracy of position measurement is stable, and the measurement position is selected as the reference position.

3-5. Change of reference position selection condition The reference position selection condition may be changed according to the moving state of the moving body. For example, the azimuth difference threshold used in the moving direction change condition may be changed using the moving speed of the moving body measured using a Doppler of satellite signals.

  FIG. 13 is a diagram illustrating a data configuration example of the azimuth difference threshold setting data that defines the azimuth difference threshold. In this azimuth difference threshold setting data, the moving speed and the azimuth difference threshold are defined in association with each other. This azimuth difference threshold value can be applied to, for example, the first azimuth difference threshold value and the second azimuth difference threshold value in the first and second conditions of the moving direction change conditions shown in FIG.

  The smaller the moving speed of the moving body, the smaller the azimuth difference threshold value is determined. When the moving body is moving at a high speed, the moving body cannot suddenly change a large moving direction. For this reason, the larger the moving speed in the moving direction, the smaller the azimuth difference threshold value, and relaxes the criterion for determining that the moving direction has changed.

  As another example, for example, the elapsed time condition shown in FIG. 5 can be changed according to the moving speed of the moving body.

  FIG. 14 is a diagram illustrating a data configuration example of threshold time setting data in which a threshold time with respect to the elapsed time is determined. In this threshold time setting data, the moving speed and the threshold time are associated with each other. As the moving speed increases, a shorter time is set as the threshold time. The higher the moving speed, the longer the moving distance traveled by the moving body. For this reason, if the time interval for setting the reference position is lengthened, an error is likely to occur in the calculated cumulative movement distance. Therefore, the threshold time is shortened so that the reference position is set at a shorter time interval as the moving speed increases.

3-6. Position jump condition In the above embodiment, the occurrence of position jump is determined by comparing the movement distance (position reference calculation distance) obtained from the context of the measurement position with the movement distance (speed reference calculation distance) obtained from the movement speed. However, the position jump condition for determining the position jump is not limited to this.

  Specifically, for example, whether the moving direction (positional direction) of the moving body obtained from the context of the measurement position matches the moving direction (velocity direction) of the moving body measured using the Doppler of the satellite signal. May be included in the position skip condition. In this case, for example, in addition to the case where the position reference calculation distance and the speed reference calculation distance deviate by a certain amount or more, the position jump occurs when the position azimuth and the velocity azimuth deviate by a certain amount or more. You may make it determine.

DESCRIPTION OF SYMBOLS 1 Runners watch, 2 Body part, 3 Band part, 4 Operation button, 5 Liquid crystal display, 6 Speaker, 7 GPS antenna, 8 Rechargeable battery, 9 Control board, 10 Processing part, 20 GPS module, 30 Sensor part, 40 operation Unit, 50 display unit, 60 sound output unit, 70 communication unit, 80 clock unit, 90 storage unit

Claims (8)

Moving distance calculation device
Measuring a position and a moving direction of the moving body periodically,
A step of selecting a measurement position change of the moving direction satisfies the reference position selection condition to the reference position,
Regardless of whether or not filled with the reference position selection condition, the calculated distance connecting the reference position, and by Rukoto using the distance to the latest measurement position from the latest reference position, the accumulated travel distance at a predetermined time interval And steps to
Displaying the latest cumulative travel distance on the display unit at the predetermined time interval;
Run the
Moving distance calculation method. In claim 1,
Wherein the step of selecting determines a moving direction of the latest reference position, the moving direction at the measurement position, the Rukoto using an angle formed by the, whether the reference position selection condition is satisfied,
Moving distance calculation method. In claim 1,
It said step of measuring is by Rukoto using Doppler satellite signals, including a first direction measuring step of measuring the movement direction of the movable body,
Wherein the step of selecting includes a moving direction of the latest reference position measured in the first direction measuring step, by Rukoto using the moving direction, the angle between the in the measurement position, the reference position selection condition is satisfied determines whether or not,
Moving distance calculation method. In claim 3,
It said step of measuring comprises the second direction measuring step of measuring the movement direction from the context of the measuring position,
The moving distance calculation device
The first of the first moving direction at said measured measurement position direction measuring step, and the second moving direction at said measured measurement position in the second direction measuring step a predetermined approximation condition If not , execute the step of suppressing the selection of the measurement position to the reference position;
Moving distance calculation method. In any one of Claims 1 thru | or 4,
Said step of measuring measures a moving speed of the moving object,
The moving distance calculation device
Executing the step of changing the reference position selection condition according to the moving speed of the moving body;
Moving distance calculation method. In any one of Claims 1 thru | or 5,
The moving distance calculation device
Determining whether the measurement position satisfies a predetermined position jump condition;
Suppressing the selection of the measurement position to the reference position when the position skip condition is satisfied;
When the latest positioning position does not satisfy the position skip condition and the elapsed time since the latest reference position is selected satisfies a predetermined elapsed time condition, the latest measurement position is set as a new reference position. The steps to select,
Run the
Moving distance calculation method. In any one of Claims 1 thru | or 5,
The moving distance calculation device
Determining whether the measurement position satisfies a predetermined position jump condition;
Suppressing the selection of the measurement position to the reference position when the position skip condition is satisfied;
Run
The measuring step measures the moving speed of the moving body by using a Doppler of a satellite signal,
Wherein the step of calculating, when the position skip condition is satisfied, the cumulative moving distance calculated last time, and the Rukoto using the moving velocity, calculates the current accumulated travel distance,
Moving distance calculation method. A measuring unit for periodically measuring the position and moving direction of the moving body;
A selection unit for selecting a measurement position where a change in the moving direction satisfies a reference position selection condition as a reference position;
Regardless of whether or not filled with the reference position selection condition, the calculated distance connecting the reference position, and by Rukoto using the distance to the latest measurement position from the latest reference position, the accumulated travel distance at a predetermined time interval A calculating unit to
A display control unit for displaying the latest cumulative movement distance on the display unit at the predetermined time interval;
Including
Moving distance calculation device.

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